Naphthenate sized products



Patented Jan. 5, 1954 NAPHTHENATE SIZED PRODUCTS Frank M. McMillan, Berkeley, and Robert D. Sullivan, Oakland, Calif., assignors to Shell Development Company, San Francisco, Calif., a corporation of Delaware No Drawing. Application June 29, 1948,

' Serial No. 35,988

6 Claims.

This invention relates to an improved method of sizing fibrous materials such as paper, cardboard, textile threads, fabrics and the like. It deals with a new process whereby such materials may be sized more efficiently and economically and with the sized products of more advantageous properties thereby obtained.

Rosin, parafiin wax, natural and synthetic resins, asphalt, tars and a great many other materials have been suggested as suitable materials for sizing paper or the like. All of these sizing materials have disadvantages of one kind or another, some being more expensive than is desirable and others being of inadequate waterproofing ability or having other characteristics which limit their usefulness. It is an important object of the present invention to provide a method of sizing which overcomes these disadvantages of prior sizes and which will be more economical in commercial practice. Another object is to provide improved articles of manufacture particularlysized paper and the like, which are more water-resistant than prior products of a similar type. Still other objects and advantages of the invention will be apparent from the following description of the invention in some of its more preferred forms, it being understood that the invention is not limited thereto but is broadly applicable and capable of many variations.

It has been found that fibrous materials, particularly fibers of cellulose and the like, may be advantageously sized with salts of naphthenic acids of low molecular weight having high acid numbers, i. e., acid numbers of 200 or greater, preferably acid numbers of about 225 to 400. The ordinary naphthenates of commerce are thus not suitable for use according to the invention since they generally contain undesirably large amounts of naphthenic acids having acid numbers of less than 260. However, naphthenates of the required characteristics may be obtained from commercial naphthenate mixtures by treatment with acid to form the free naphthenic acids followed by distillation of the latter to take off a fraction having the desired high acid number. Especially advantageous sources of naphthenates having desirable sizing properties are those obtainable in the refining of properly selected fractions of petroleum such, for example, as gasoline or kerosene fractions, gas oil or the like. Methods which may be used in obtaining the naphthenates from such sources include, for example, alkali treatment of acid-refined petroleum distillates, or the caustic distillation of mineral oils, particularly oils from Texas and California crudes, to obtain oil-containing naphthenates which may be used as such or may be partially purified by acid treatment or more completely deoiled by dispersion in an aqueous medium followed by de-emulsification in the presence of a solvent for the oil. Where more highly purified naphthenates are desired, they may be produced by known methods, including washing with seat water or treatment to remove sulfur compounds, for example. It' is not necessary, however, that the naphthenates of naphthenic acids having acid numbers greater than 290 be used in pure form since it is quite feasible to use them with hydrocarbons including the hydrocarbons from which they are derived. Indeed, it is quite feasible to employ the naphthenates according to the invention along with other materials which may or may not have sizing properties of their own. Most preferably, other sizing materials such, for example, as rosin size or higher boiling hydrocarbons are used when the naphthenates of naphthenic acids of high acid number are employed in the form of mixtures with other materials.

The naphthenates are preferably used as the sodium salts since they are generally less expensive and have desirable solubility characteristics. However, other alkali metal salts, particularly the potassium salts, may also be employed as may also alkaline earth metal salts, such as the calcium and magnesium salts, aluminum salts or other inorganic salts. When using aluminum and like water-insoluble salts it is desirable to use an emulsifying agent for the naphthenate salt to insure its uniform distribution on the fibers. To this end, a small amount, usually about 0.1% to 5% by weight of the total amount of sizing agent employed, of a suitable soap is preferably used. Fatty acid soaps, higher alkyl sulfate salts, o ganic sulfonic acid salts particularly alkyl aryl sulfonates, naphthenates of naphthenic acids having acid numbers less than 200, sodium rosinate, and the like are suitable. For certain purposes it may be desirable to use ammonium or amine salts of the naphthenic acids of acid number 200 or greater. Water-soluble amines such, for instance, as dimethylamine, propylamine, cyclohexylamine, the ethanolamines, etc. are suitable for forming naphthenates which may be used in the process of the invention.

The naphthenates corresponding to naphthenic acids of acid number 200 to 400 or more may be used simply and efficiently for sizing fibers, for example, by adding the naphthenate to an aqueous slurry of the fibers and, after stirring to insure uniform distribution of the naphthenate the like are suitable. added to the fiber before-oralong-with-the naphpulp, isdesirable during precipitation. essary, the pH may be controlled by adding-dilute .acid in the beater. About 25 grams of aluminum sulfate per kilogram of-.dry: stuff inthe beater ves satisfactory precipitation. Too. much. alusize and fibers, precipitating the sizing agent with a suitable precipitant such as paper makers alum or the like. The naphthenates of high acid number naphthenic acids thus have the advantage not only of imparting exceptional water resistance to cellulose fibers and the like, but also: of being adapted to ready. use-in the sameequipment as conventional sizes. Thus, in sizing paper according to the invention, for instance, a sodium naphthenate of a naphthenic acid of acid number 200 to 400 may be added to any suitable "paper pulp in the beater engine at anys-stage of beating, although as a rule it is moreadvantageously-introduced when the beating haszbeen substantially completed, or the sizing may be carried out in the Jordan machines or at themscreens. Awide range of precipitants may be used forfixingi the naphthenate sizes on the fibers. Alum, aluminum sulfate, aluminum chloride, calcium chloride, acids such as sulfuric of hydrochloric acid, and The precipitant may be thenate size but generally it'ispreferred to add it a sufficient time after adding the size to provide an adequate interval for uniform distributioncof the" size before introduction of the precipitant. A pH of about-4.5 to 6, depending on the type of If. necminum in the paper should be avoided as it adversely affects the permeability -to'water' and. the

. age resistance. of the paper.

Theamount of naphthenate size which it will be most advantageous to employ-will depend: on

3 the nature of the fibrous material being. treated,

the purpose for-which it-is intended, the typeof naphthenate chosen, andv the method of its-application. As little-as 0.2%-based on the dry weight of the paper is effective, but. up to or more may be used, the preferred-range being .usually. about 0.5% to about 3%.

As previously pointed out, it may sometimes be desirable to use the naphthenates of.-high acid number. naphthenic .acids in conjunction with other. sizing materials. Thus, emulsions of oils .or waxes such asparafiin, ceresin-andmontan waxes,. for example, .are .useful when .used in combination with highacid number. naphthenates. Hydrocarbons .such as lubricating .oils, spindle. e11, asphalts, bitumens, .etc.. may likewise be used. However, there. are specialadvantages in using cyclic extracts ofpredominantly .aro-

matic. and naphthenic nature, such .as, are obtainable by extracting petroleumor relatedoils,

' including hydrogenation products of coalandthe like, with solvents whichare selectiveLforrnonparafiinic constituents. .A wide variety. of. polar solvents may be used for the preparation ofsu'ch extracts, liquid sulfur dioxide, phenol, cresylic acid, furfural, beta,beta-ldich1orethylv ether,..nitrobenzene, the sulfolanes and sulfolenes, and .the like being typical examples of suitable solvents which may be advantageously used. "Combinations of solvents, as phenol with cresylicv acid or liquid sulfur dioxide with'benz'ene or toluene, for instance, are useful and the use of the. so-called double solvent process employing .mutually im- .miscible solvents, e. g. cresylic acid with propane,

also gives suitable extracts. .Extracts of heavier petroleum oils such as the lubricating oilsand residual. stocks are especially usefulin conjunction with high-acid number naphthenatesinacvania'type oils.

cylinder stocks -which. vmay, :for-.:instance, range ..injgravityifromi to 8".'API at""60".. F. They may be obtained from any mixed type petroleum woil such as Mid-Continent or Coastal or California crude or, in lower yields, from Pennsyltion withHJnaphthenates of high acid number naphthenicacids;extracts boiling above 300 C. at 760 mm. Hgpressure are preferred, and most preferably extracts boiling from about 125 C. to

300 C. at 1 mm. Hg pressure are used. The

:' more viscous extracts usually give emulsions with "themost desirable sizing properties.

:reason fextracts within the viscosity range of For this about '75 to 5000 at 2105 F., S. U. 8., have advantages. It isoften advantageous to fractionate-the initial extractto separate fractions of especially advantageous properties; thus; for. instance, it hasbeen found. thatiithe higher boiling 50% to .of an, E'deleanu extractof. lubricating oil gives superior sizing when used with-naphthenates according to "the invention.

The proportion of naphthenate of high acid number to hydrocarbon used when: employing suchmixtures for, paper sizing according tothe invention-can be variedbut: as a rule will .be such as correspondsto about 25% totabout 99%, more preferably 50% to 99 byweightof'naphthenate based on the total weightiof naphthenate'and hydrocarbon. Such hydrocarbon 'should' be used in the form of an. aqueous emulsion; to whichend a small amount, usually*about"2%lto 10% by weight of thenaphthenate and hydrocarbon present, of an emulsifying agentshould" be 'employed. Soap, alkyl' sulfate salts, 'sulfonic' acid salts, particularly alkylt ar'yl sulfonates, sodium rosinate and thelike may be used as emulsify- 'ing agents. Themostadvanta'geous sizingemulsions, however, are those" made" from naphthenates without otheremulsifying agents.

The'following example shows the results'obtainable according totheinvention in'comparison withsizing with naphthenatesof low acid number napthenic acids.

-Emample Deoiled napthenates. were .used .as the sole sizing agent for kraft pulp. -The.deoiled naphthenic acids were completely saponifiedwith so dium hydroxide solution to forms; 10%. aqueous solution of sodium. naphthenate. .The (moontent ofthe-deoilednaphthenates wasbetween 3% ..and- 10% byweight. v.About 2% of. sodium .naphthenate based-upon the dry. weight of. pulp was used and the-beaten pulp was stirred for 15 minutes with .the napthenatesbefore adding -3 %..of

.paper. makers Ialum. as. precipitant,-.af.ter which 15 minutes additional stirring. was. givenlthe pulp. Comparative tests were. carried out onsheets made from the two pulpsthus sized. Thesheets were prepared inv a 'standardhan'd mold, followed .by pressing. at 50. pounds. for '2 minutes. The sheets were'dried at 60,'C'. 70..C.. .and tested after conditioning the test-samples at 70. F. and 50% relative humidity. 'The resulting sheets were compared as. to .wetting.time .(i. e., time .for. .the paper' floating on waterto show wetspots on its upper surface). and ink. absorption (i.- e, thearea stained by. 0.05.ml..of.ink dropped on .the surface .and. allowed to. dry) As. shown by. the following For use in sizing in combina-' results, the naphthenates of higher acid number were by far the superior sizing agents.

Water Wet- Absorption Acid No. of ting Time of Ink (area Naphthenate of Paper of dry spot,

(hours) blank 0. 190

Similar good results are obtained when sulfite pulp is substituted for the kraft pulp.

It will thus be seen that the new process of the invention oifers many advantages over prior methods of sizing and gives sized products of superior properties. It will also be apparent that the invention is not limited to the applications given by way of illustration nor to details of operation disclosed. Thus, for example, instead of the naphthenic acid salts, the corresponding free naphthenic acids having acid numbers of 200 or greater, preferably 225 to 400, may be used as the sizing agent and these naphthenic acids and their salts will be referred to generically hereinafter as naphthenates. Still other variations may be made in the process of the invention which will be understood as not dependent upon any theory advanced in explanation of the improved results which are obtained.

We claim as our invention:

1. A paper product comprising sized cellulose fibers containing about 0.5% to about 5% by Weight of sizing agent wherein the effective sizing agentis essentially naphthenates of naphthenic acids having an average acid number greater than 200 but not greater than about 400, together with a mixture of cyclic components of petroleum soluble in solvents which are selective for non-parafi'inic constituents thereof.

2. A paper product comprising cellulose fibers having distributed on their surface about 1% to about 5% by weight of the dry fibers of a naphthenate of a naphthenic acid having an acid number of 225 to 400, together with cyclic constituents of a lubricating oil fraction of petroleum soluble in solvents which are selective for non-parafiinic constituents in proportions such that the naphthenates correspond to about 25% to 97% of the total weight of naphthenates and said cyclic constituents.

3. A fibrous product comprising sized cellulose fibers having distributed on their surface 0.2% to about 10% by weight of the dried fibers of naphthenates of naphthenic acids having an average acid number greater than 200 but not greater than about 400, together with a mixture of cyclic components of petroleum soluble in solvents which are selective for non-paraffinic constituents thereof.

4. A fibrous product in accordance with claim 3 wherein the sized fibers are kraft paper pulp fibers, and said cyclic components are derived from a lubricating oil fraction of petroleum.

5. A fibrous product in accordance with claim 3 wherein the naphthenates are sodium naphthenates essentially derived from naphthenic acids having acid numbers of at least 225 but not greater than 400.

6. A fibrous product in accordance with claim 3 wherein said cyclic components are derived from a lubricating oil fraction of petroleum and are present in proportions such that the naphthenates correspond to about 25% to 99% of the total weight or" naphthenates and said cyclic components.

FRANK M. MCMILLAN. ROBERT D. SULLIVAN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,519,803 Sellers et a1 Dec. 16, 1924 1,920,483 Senftner Aug. 1, 1933 2,332,226 Hutchins Oct. 19, 1943 2,340,035 Zimmer et al Jan. 25, 1944 2,377,359 Musher June 5, 1945 2,423,619 Roon July 8, 1947 2,447,475 Kaberg et a1. Aug. 17, 1948 2,538,742 Willey Jan. 16, 1951 FOREIGN PATENTS Number Country Date 364,564 Germany Nov. 27, 1922 525,338 Great Britain Aug. 27, 1940 OTHER REFERENCES Gershzon, Chemical Abstract, vol. 33, p. 8989*. Gershzon, Chemical Abstract, vol. 34, p. 3119. Chemical Reviews, vol. 30, pages 97-111 (1942). 

1. A PAPER PRODUCT COMPRISING SIZED CELLULOSE FIBERS CONTAINING ABOUT 0.5% TO ABOUT 5% BY WEIGHT OF SIZING AGENT WHEREIN THE EFFECTIVE SIZING AGENT IS ESSENTIALLY NAPHTHANATES OF NAPHTHENIC ACIDS HAVING AN AVERAGE ACID NUMBER GREATER THAN 200 BUT NOT GREATER THAN ABOUT 400 TOGETHER WITH A MIXTURE OF CYCLIC COMPONENTS OF PETROLEUM SOLUBLE IN SOLVENTS WHICH ARE SELECTIVE FOR NON-PARAFFINIC CONSTITUENTS THEREOF 